Various types of secure content may be received to be played back on a computer. For example, pay per view video or proprietary content may be received on a computer system for playback. Digital versatile disc (DVD) content may also be played on computers. The content may arrive in an encrypted manner and, therefore, cannot be easily intercepted in the route to the receiving computer.
Newer content protection schemes like the Advanced Access Content System (AACS) is a standard for content distribution and digital rights management, intended to restrict access to and copying of optical discs and DVDs. See “Advanced Access Content System: Introduction and Common Cryptographic Elements” Rev 0.91 or Rev 0.951. The standard has been adopted as the access restriction scheme for HD DVD and Blu-ray Disc (BD).
However, once the content arrives at the computer, it may be decrypted for playback. Licensed players use a DRM (digital rights management) device key for extracting a title key which is then used for decrypting the media content. Typically, DRM device keys are protected using Tamper Resistant Software methods which have been historically broken often thus exposing the device keys for use by unlicensed players for unauthorized content ripping. Once decrypted, it may be accessed by malevolent software on the computer system and stolen by unauthorized entities. Unauthorized copies of software, DVD discs, games, videos, and other content may be made in this way.